So while it's crazy to not let Star Wars fans cosplay, it wouldn't be crazy to let Star Wars fans, a toxic fanbase that's split into factions out to ruin one another's experiences, dress exactly like Disney employees. That's how you wind up with a million angry parents demanding a refund because a Jedi Knight called their tween a feminazi SJW for liking Rey.
But those feeling foam armor FOMO can take a page out of OG Disneyland fans, who've figured out a cosplay loophole. Made popular by the eponymous blog, "DisneyBounding" is the underfunded school play equivalent of cosplaying whereby people dress in regular street clothes which match the color scheme, style, and theme of their favorite Disney costumes. This removes any confusion with Disney staff while still allowing fans to dress up for the high ceremony of visiting a funfair in Florida. (There's presumably a subgroup of fans bounding as Donald Duck, but we're assuming that blog's behind a paywall.)